Extroverts are happier than introverts; optimists are happier than pessimists; married people are happier than singles, though people with children are no happier than childless couples; Republicans are happier than Democrats; people who attend religious services are happier than those who do not; people with college degrees are happier than those without, though people with advanced degrees are less happy than those with just a BA; people with an active sex life are happier than those without; women and men are equally happy, though women have a wider emotional range; having an affair will make you happy but will not compensate for the massive loss of happiness that you will incur when your spouse finds out and leaves you; people are least happy when they’re commuting to work; busy people are happier than those with too little to do; wealthy people are happier than poor ones, but only slightly.

It’s not easy to figure out why some place are happy and others are not. Anyone looking for easy theories is in for a surprise.

The happiest places, he explains, don’t necessarily fit our preconceived notions. Some of the happiest countries in the world— Iceland and Denmark, for instance— are homogeneous, shattering the American belief that there is strength, and happiness, in diversity. One finding, which Veenhoven just uncovered, has made him very unpopular with his fellow sociologists. He found that income distribution does not predict happiness. Countries with wide gaps between the rich and poor are no less happy than countries where the wealth is distributed more equally. Sometimes, they are happier… With each click of the mouse, I encounter mysteries and apparent contradictions. Like this: Many of the world’s happiest countries also have high suicide rates. Or this one: People who attend religious services report being happier than those who do not, but the world’s happiest nations are secular. And, oh, the United States, the richest, most powerful country in the world, is no happiness superpower. Many other nations are happier than we are.

Friends are a big part of happiness. One of the secrets to Iceland’s happiness might be that it is so small, homogenous and tight knit that people run into friends wherever they go.

On a practical level, Iceland’s smallness means that parents needn’t bother with that old bromide about not talking to strangers. There are no strangers in Iceland. People are constantly running into friends and acquaintances. It’s not unusual for people to show up thirty minutes late for work because en route they encountered a parade of friends. This is a perfectly valid excuse, by the way, for being late. The Icelandic equivalent of traffic was hell.

Geneticists have found that everyone in the country is related to everyone else, going back seven or eight generations. Icelanders can go to a website and find out how closely they are related to a colleague, a friend— or that cutie they slept with last night. One woman told me how unnerving this can be. “You’ve slept with this guy you’ve just met and then the next day you’re at a family reunion, and there he is in the corner eating smoked fish. You’re like—‘ Oh, my God, I just slept with my second cousin.’

Bhutan is so interested in the happiness of its citizens the government eschews Gross National Product for a Gross National Happiness scale.

In a nutshell, Gross National Happiness seeks to measure a nation’s progress not by its balance sheet but rather by the happiness— or unhappiness— of its people. It’s a concept that represents a profound shift from how we think about money and satisfaction and the obligation of a government to its people.

America’s place on the happiness spectrum is not as high as you might think, given our superpower status. We are not, by any measure, the happiest nation on earth. One study, by Adrian White at the University of Leicester in Britain, ranked the United States as the world’s twenty-third happiest nation, behind countries such as Costa Rica, Malta, and Malaysia. True, most Americans— 84 percent, according to one study— describe themselves as either “very” or “pretty” happy, but it’s safe to say that the United States is not as happy as it is wealthy.

So what can we learn from the unhappiest place on the planet?

Moldova is the unfortunate holder of that title.

Yes, Moldova is poor, but as Weiner points out, that’s not the source of the trouble.

Many countries are poorer than Moldova yet happier. Nigeria, for instance, or Bangladesh. The problem is that Moldova ns don’t compare themselves to Nigerians or Bangladeshis. They compare themselves to Italians and Germans. Moldova is the poor man in a rich neighborhood, never a happy position to be in.

And don’t think that democracies and freedom are what makes a country happy — actually that’s backwards.

It’s not that democracy makes people happy but rather that happy people are much more likely to establish a democracy. The soil must be rich, culturally speaking, before democracy can take root. The institutions are less important than the culture. And what are the cultural ingredients needed for democracy to take root? Trust and tolerance. Not only trust of those inside your group— family, for instance— but external trust. Trust of strangers. Trust of your opponents, your enemies, even. That way you feel you can gamble on other people— and what is democracy but one giant crapshoot? Thus, democracy makes the Swiss happier but not the Moldovans. For the Swiss, democracy is the icing on their prosperous cake. Moldovans can’t enjoy the icing because they have no cake.

Lesson number one: “Not my problem” is not a philosophy. It’s a mental illness. Right up there with pessimism. Other people’s problems are our problems. If your neighbor is laid off, you may feel as if you’ve dodged the bullet, but you haven’t. The bullet hit you as well. You just don’t feel the pain yet. Or as Ruut Veenhoven told me: “The quality of a society is more important than your place in that society.” In other words, better to be a small fish in a clean pond than a big fish in a polluted lake.

Lesson number two: Poverty, relative poverty, is often an excuse for unhappiness. Yes, Moldovans are poor compared to other Europeans, but clearly it is their reaction to their economic problems, and not the problems alone, that explains their unhappiness. The seeds of Moldovan unhappiness are planted in their culture. A culture that belittles the value of trust and friendship. A culture that rewards mean-spiritedness and deceit. A culture that carves out no space for unrequited kindness, no space for what St. Augustine called (long before Bill Clinton came along) “the happiness of hope.”

Overall, after criss-crossing the world for answers on happiness, what did he come away with?

Money matters, but less than we think and not in the way that we think. Family is important. So are friends. Envy is toxic. So is excessive thinking. Beaches are optional. Trust is not. Neither is gratitude.